1. Field of the invention
The present invention relates to a new and improved system for processing a flexible web, such as a web comprising paper, for producing documents and/or envelopes therefrom.
The system may serve for processing one or several webs, preferably consisting in part or fully of paper, for producing documents therefrom. The term document as used here is meant to refer to a printed form such as a business form, preferably produced in larger lots, each document of each lot being arranged to comprise at least in part non-repetitive information and/or data, i.e. information and data that vary from document to document and represent for example the name and address of the recipient and information and/or data concerning him individually. In addition to the data varying from document to document, the documents may contain printed information and data remaining the same for all of the produced documents or at least for a lot thereof; such information or data may be the name of the firm or the organization that produces the documents, and/or that mails them, furthermore the names of the documents, as for example "Confirmation of Order" or "Invoice", as well as dividing lines for separating columns and spaces Subsequent to being printed upon the web may be shaped in various ways and may be cut up for example into sheets to be packed into different envelopes for mailing purposes. The system may also serve for folding the printed documents and connecting them, folded and at predetermined locations, to form of each document an envelope which may be torn open and which may contain on the outside the address of the recipient, and on the inside informations destined for the recipient. Instead of producing documents the system may be adapted to produce envelopes from a web for mailing documents therein. In the course of being produced the envelopes may be provided for example with the address of the sender, with other repetitive data and/or with a window.
2. Description of the Prior Art
The U.S. Pat. No. 4,611,799 discloses systems in which a virgin paper web, i.e. non-printed upon and non-perforated, is passed through a series of individual, autonomous units or devices and is converted into documents in processing steps carried out in the various devices partially or fully synchronously, i.e. on line. One such system disclosed in the aforementioned patent comprises a feed spool for feeding a web of virgin paper, a shaping device for perforating a marginal strip at each of the two longitudinal margins of the paper web, a printing device for printing repetitive data, a printing device for printing certain non-repetitive variable data dictated by a computer, and a second shaping device for cutting off the perforated marginal strip of the paper web, as well as for cutting up the paper web into sheets. Another system disclosed in said U.S. patent comprises a feed spool device, a shaping device for perforating the two longitudinal margin strips of the paper web, a printer for printing non-repetitive, variable information and data and a feed spool device for reeling off the web printed upon. During the operation of such or similar systems used in actual practice, the transporting means associated with the various devices are controlled by means of control devices in a way, to have the paper web form loops between the devices. This makes it possible to avoid excessive tension stresses in the paper web, even though the transporting means of the printing devices, controlled by a computer and adapted for printing the non-repetitive, variable information and data and comprising stepping motors, are arranged to move the paper web intermittently; at the same time the feed spool and shaping devices normally comprise relatively heavy and inert, transporting means adapted to be accelerated and braked at slow rates only. The systems known from U.S. Pat. No. 4,611,799 thus permit the on-line processing of a virgin paper web into completed documents; they possess however the disadvantage, that they require a relatively large number of different devices and separate transporting means; they are thus relatively expensive and their room requirements are considerable.
Shaping units used at present in practice generally comprise a frame, transporting means, and two processing members for processing the paper web; the processing members are supported on the frame rotatably around parallel rotational axes and adapted to be driven by a drive motor and to allow the paper web to be passed between them during operation. The devices serving for perforating the two longitudinal marginal strips of the paper web and arranged to face away from each other comprise for example two processing members. One of these serves as a matrix or die and--for punching two rows of holes--each comprises a number of holes or depressions distributed over its periphery and engaged during operation by fixedly held punches distributed over the periphery of the other processing member. Because of the wear incurring during the punching operation the punches must be replaced from time to time; this is accomplished in the known devices by individually replacing the punches in the processing member mounted in the frame. This has the disadvantage, that the device, and thus the entire system which the device is a part of, must be put out of operation for a relatively long duration, lasting for example for several hours. Furthermore, the two processing members of the known devices are supported in the frame non-adjustably, so that no possibility is provided for compensating for inaccuracies of fabrication; furthermore considerable friction losses may arise under certain conditions, the compensation of which may require drive motors of large capacity.
The devices conventionally used in practice for cutting off sheets from a paper web similarly comprise two processing members, specifically, two cylinders disposed one above the other and supported on the frame rotatably around two parallel axes and adapted to be driven by means of a drive motor. The lower cylinder processes a smooth, cylindrical support surface and consists at least in part of a particularly hard steel of a special kind; the upper cylinder, on the other hand, consists only of a semi-hard steel and carries at least one cutting knife parallel to its rotational axis. Each time the knife (or the knives) of the upper cylinder passes during operation by the lower cylinder, it strikes the paper web passed between the cylinders as well as the lower cylinder, and cuts a sheet off the paper web. In these devices too, the periodic replacement of the knife requires each time a relatively long interruption in the operation of the device and of the entire system. An additional disadvantage of these devices consists in that the impacts which occur while cutting off the sheets produce much noise and strong vibrations, as well as deflections of the cylinders. Since such deflections increase with the length of the cylinder, it becomes difficult or impossible to cut up paper webs having a width exceeding a certain critical value. Furthermore, the vibrations generated by the impacts and the large frictional forces which occur, demand a strong frame and a strong drive motor, thus increasing the room requirements as well as the manufacturing and operational costs. Furthermore, two cylinders of a certain diameter are only suited to cut off sheets having a length equal to the perimeter of the cylinder, or, if the upper cylinder comprises more than one knife, to the cylinder perimeter divided by the number of knives. Similar disadvantages exist in those known shaping devices, in which the knives comprise interrupted cutting edges rather than a continuous cutting edge, their purpose being to generate rows of holes to run perpendicular to the longitudinal direction of the web, and to serve as predetermined tear lines.
In other known shaping devices serving different purposes, such as cutting off the perforated margin strips or intermittently connecting two or more paper webs in a stamping process known as crimp lock process, or by gluing, it is generally required to periodically replace the rotatably supported processing members totally or partially, and/or at least to clean them; this, too, frequently requires relatively long interruptions in the operation of the system.
As mentioned before, it has been known from the U.S. Pat. No. 4,611,799 to equip such systems with a printing device adapted for printing repetitive information and data in addition to the printing device intended for printing non-repetitive, variable information and data determined by a computer. Printing devices for printing repetitive information and data also comprise two processing members, between which the paper web is passed through, at least one of the processing members being mounted for rotation, and the other being provided with a printing die (matrix). The replacement of this printing die may require--in the known printing devices--a relatively long interruption in the operation of the entire system.